The problem of accidental falls among elderly people is a major health problem. More than 30 percent of people more than 80 years old fall at least once during a year and as many as 3,000 aged people die from fall injuries in Sweden each year. Preventive methods can be used but falls will still occur and with increased average lifetime, the share of population above 65 years old will be higher, thus resulting in more people suffering from falls.
Different fall detectors are available. One previously known detector comprises an alarm button worn around the wrist. Another detector, for example known from US 2001/0004234, measures acceleration and body direction and is attached to a belt of the person. But people refusing or forgetting to wear this kind of detectors, or being unable to press the alarm button due to unconsciousness or dementia, still need a way to get help if they are incapable of getting up after a fall.
Thus, there is a need for a fall detector that remedies the above-mentioned shortcomings of prior devices.
In certain instances, it might also be of interest to provide for fall prevention, i.e. a capability to detect an increased risk for a future fall condition, and issue a corresponding alarm.
Intelligent optical sensors are previously known, for example in the fields of monitoring and surveillance, and automatic door control, see for example WO 01/48719 and SE 0103226-7. Thus, such sensors may have an ability to determine a person's location and movement with respect to predetermined zones, but they currently lack the functionality of fall prevention and detection.